In an effort to improve the volumetric efficiency of avionics box designs and their mounting structure, the avionics electronic industries have developed a connector commonly referred to as a "blind-mated" connector. In such design, a base plate member with male plugs or pins fixed on one side thereof is mounted to a support structure which is intended to support the avionics box. A plurality of receptacles are provided in a connector plate member on the rear of the avionics box at locations suited for reception of the male plugs as the box is guided into place by an appropriate guide means. In order to allow for tolerance build-up and to insure complete mating of the connector plugs and receptacles, the connector plate member is mounted on one or more compression springs which are preloaded to a combined force greater than that which is necessary to overcome the friction force encountered in the mating of the connector pins and receptacles. The connector plate member is mounted and positioned such that, with tolerances falling to one side of the connection, the preload compression springs will just begin to compress under their preload length as the connector pins and receptacles become fully engaged. Also, the compression springs are allowed a degree of extension travel which is sufficient to accommodate a tolerance stack-up to the other side of the connection.
Due to the large forces required to mate some connectors, which can be as high as 350 lbs. or more for some connectors, the spring preload must be quite high to insure full mating. In the course of accommodating tolerance stack-ups, the load can be as much as double that required for a tolerance-free connection, thereby leading to a requirement for individual spring forces of up to 85 lbs. for some connectors. In such conventional designs, these spring forces are applied to the structural supports so long as the avionics box remains installed, even though the preload is not needed once the connectors are fully engaged. A result is that the constant application of the preload has significant impact on the connector support requirements in terms of increased stiffness, strength, and ultimately, weight. Furthermore, when several avionics boxes share a common support structure, the combined forces from their preload springs can be very significant, resulting in additional structure and more severe weight impacts.
In U.S. Pat. No. 4,789,351 there is shown a blind-mated connector wherein the jack half of a plug and jack connection is spring biased to accommodate tolerance variations. U.S. Pat. No. 4,846,714 shows a quick disconnect connector wherein a spring biases a male member into connection with a female member and releasable locking jaws are employed to lock the members together. In U.S. Pat. No. 5,213,532 there is shown a lever system for aligning a load item with respect to a support structure for connection therewith and the application of a preload to the connection interface. U.S. Pat. No. 3,781,039 shows two parts of a coupling retained in coupled relationship by ball detents held captive in one part and urged radially inward into a recess on the external surface of the other part by a spring biased sleeve.
However, it is to be noted that in the patented devices cited above, the loads applied by compressive springs are maintained so long as the connection is in effect.